Electron tube electrode



July 16, 1957 A- P. VERMETTE ETAL 2,79

ELECTRON TUBE ELECTRODE Filed Jan 5, 1956 I INVENTOR. 4455mm! VERMETTE i v BY ow/2.44 E. MYER 4%. TTORWE) United States Patent ELECTRQNTUBE ELECTRGDE Albert P. Vermette, Marion, and Lowell E. Myers, Fort Wayne, ind, assignorsto Radio Corporation of America, a corporation of Delaware Application .lanuary 3, 1956, Serial No. 557,010

a Claims. (Cl. 313-356) This invention relates to an electron tube electrode. In particular, it relates to an improved sheet metal electrode structure.

One type of electrode, commonly used as an anode, includes a tubular structure having side Wings and ears integral with the wings. The ears extend beyond one end of the tubular structure and are adapted to be inserted into and through an aperture in an electron tube spacer plate for locking the electrode to the plate. The wings and ears referred to are commonly made of two pieces of sheet metal. Heretofore, this has resulted in ears having relatively sharp side edges. The sharp edges give rise to ear deformation during handling and mounting. Furthermore, in mounting the electrode, the sharp ear edges often abrade the spacer plate at portions thereof defining the aperture aforementioned. This abrasion usually results in a poor positioning of the electrode with respect to other tube elements. Also, thermal expansion and contraction of the electrode during normal tube operation often gives rise to a sawing action by the elec trode ears against the spacer plate; this sawing action enlarges the spacer plate aperture and results in poor tube performance.

Among the objects of the invention are the provision of an improved electrode structure having sheet metal ears free of relatively sharp side edges and adapted to be extended through and to be locked to a spacer plate without abrasion of the plate.

The foregoing and related objects are achieved in an electron tube electrode comprised of ears having two plies of sheet metal. One of the plies is folded over the other in a novel manner to provide electrode ears having rounded side edges.

In the drawing, wherein like numerals refer to like parts:

Fig. l is a partly cut-away elevational view of an electron tube embodying the invention;

Fig. 2 is a sectional view taken through lines 2-2 of Fig. 1; and

Fig. 3 is a perspective view of a portion of the electrode of the invention shown in Figs. 1 and 2.

In Figs. 1 and 2 there is illustrated an electron tube 1 of the pentode variety, that is, a tube having an electrode arrangement comprising a cathode 2, three grids, 3, 4, and 5 concentric about the cathode, and an anode 6 around the grids. The three grids 3, 4, and 5 may be of the wound variety as shown. The electrodes are suitably spaced by means of insulating spacer plates 7 and 7. Each of the electrodes, namely the cathode 2, the three grids, 3, 4-, and 5, and the anode 6, have ears or extending portions, numbered 8 through 12, respectively. The ears and extending portions each extend through the spacer plates 7 and 7' referred to and terminate beyond the plates. The ears and extending portions are used to fix the electrodes to the spacer plates.

Referring now to Fig. 3, there is illustrated a perspective view of a portion of the anode 6 according to the invention. The anode 6 includes an elongated, rectangularly tubular structure 13 having side wings 14 and ears 12 integral with the wings, the ears extending beyond the ends of the tubular structure as shown in Fig. 1. The Wings 14 and ears 12 are made of two plies 16 and 17 of sheet metal. As shown in Figs. 2 and 3, one of the plies 16 is smoothly folded over on itself to form a two-ply ear having rounded ear side-edges 18. The ears are each provided with a longitudinally extending embossment or recess 19 ('Fig. 2). The edge of the folded-over ply 16 terminates in the recess. The ear 12 is also comprised in part of ply 17.. This part of ply 17 also has an edge in the recess 19 referred to. This disposition of the ply edges in the recess isolates them from contact with the spacer plates 7 and7 andthereby preserves them from adverse effects from the sharpness of such edges. In addition, the free ends 'of the ears are sloped to provide 'a leading endof reduced cross section'which better enables the insertion of the ears 12 through the spacer plates 7 and 7' during the mounting of the electrode on the spacer plates.

It will be noted that the ears have two thicknesses only. The use of two plies of sheet metal material for the ears, instead of the usual three plies where one of the sheet metal plies of the ear is made the desired ultimate width and another ply of the ear is made wider than ultimately desired and then folded back over the first ply so as to give a total of three plys, is advantageous in that the thinner ear construction afforded by the use of two ply ears enables the use of spacer plates having smaller apertures. Spacer plate apertures adapted to receive three ply ears must be 50 percent wider than apertures adapted to receive two ply ears. The use of smaller spacer plate apertures effects a more accurate positioning of the electrode with respect to the other electrodes and imparts greater strength to the spacer plate.

The use of the two-ply, folded-edge electrode ears affords yet another advantage. As shown in Fig. 3, only the ears have the folded-back ply construction of the invention. The folded back ply construction of the invention gives the ears 12 a less transverse extent than the wings 14. This provides ledges 20 on the wings 14. The ledges 29, together with the support afforded by the end edges 21 of the tubular structure 13, provide a relatively rigid mounting base for the spacer plates 7 and 7.

From the foregoing it will be apparent that the novel structure of the invention contributes to the provision of an electrode which not only has ears which are free of relatively sharp edges, but which also makes use of spacer plates having relatively small electrode-ear receiving aper tures and provides a relatively rigid spacer plate mounting.

What is claimed is:

1. An electron tube electrode comprising an elongated tubular structure having a wing and an ear integral with said wing, said ear extending axially beyond one end of said tubular structure, and being comprised of substantially only two plies of sheet metal, and having a longitudinally extending recess, one of said plies of said ear being smoothly folded over in a direction transverse of said structure forming a portion of the second of said plies and providing said ear with a rounded side edge, said folded over ply having a longitudinally extending edge disposed within said recess.

2. An electron tube electrode adapted to be inserted into a spacer plate, and comprising an elongated tubular structure having two wings and an ear integral with each of said wings, each of said ears extending axially beyond one end of said tubular structure, and being comprised of only two plies of sheet metal, and having a longitudinally extending recess, one of said plies of each of said ears being folded over in a direction transverse of said structure forming a portion of the second of said plies and providing each of said ears with a rounded side edge, each of said folded over plies having a longitudinally ex- I a relatively rigid mounting basefor said'spacer plate.

3. An electron tube electrode'adapted to be inserted into a spacer plate, and comprising an elongated tubular structure having a substantially rectangular cross section and two wings and an ear integral with each of said Wings,

1 each of said ears extending axially beyond one end of said tubular structure, and being comprised of only two plies V of sheet metal, and having a longitudinally extending recess, one of said plies of each of said ears being smoothly folded over in a direction transverse of said structure forming a portion of the second of said plies and providing each of said ears with a rounded side edge, each'of said folded over plies having a longitudinally extending edge disposed within said recess, said ears each having a less transverse extent than that of the wing with which it is integral for providing each of said wings with a rela- 4 7 said ears having a sloping free end providing an ear end which is adapted to be readily inserted into said spacer plate.

4. An electron tube electrode comprising an elongated structure having an integral ear, said ear comprising two plies only of sheet metal, said ear having an arcuate configuration whereby said ear has an innerand an outer surface, onerof said plies defining said outer surface and a portion only of said inner surface, the other of said plies defining the remaining portion of said inner surface, whereby a rounded edge is provided on said ear and free edges of said plies are disposed on said inner surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,372,379 lshler, Mar. 27, 1945 tively rigid mounting base for said spacer plate, one of 20 .L ITT. 

